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Impact of Blueberry Consumption on the Human Fecal Bileacidome: A Pilot Study of Bile Acid Modulation by Freeze-Dried Blueberry.
Gagnon, W, Garneau, V, Trottier, J, Verreault, M, Couillard, C, Roy, D, Marette, A, Drouin-Chartier, JP, Vohl, MC, Barbier, O
Nutrients. 2022;14(18)
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Primary bile acids (BAs) are made in the liver from cholesterol. They are released into the small intestine, where they aid fat digestion and absorption. Most BAs are reabsorbed from the gut, yet a small amount gets modified by the gut bacteria, forming secondary BAs destined for faecal excretion. Excess secondary BAs have negative health consequences. The different types of primary BAs influence many physiological functions. Such as glucose regulation, fat metabolism and absorption, intestinal inflammation and immunity, as well as gut bacteria diversity. For optimal BA metabolism, they are tightly regulated by the body, as minimal changes in BA pool and composition can have a significant impact on overall health. The composition of the BA pool can be influenced by gut bacteria, metabolic disorders, pathologies of the liver and gut, and diet. Dietary polyphenols, a plant-based compound, have been of particular interest here. This study sought to investigate the impact of supplementary freeze-dried blueberry powder (BBP), a rich polyphenol source, on the faecal BA pool composition in people at risk of metabolic syndrome. For this 11 men and 13 women were supplemented for 8 weeks. When compared to the data before the intervention, no significant changes in total BAs were observed. However, the composition of the BA pool changed leading to the accumulation of particular BAs and a reduction in secondary BA levels. This suggested that the consumption of blueberries can be considered a potential clinical intervention to aid the elimination of toxic secondary BAs. As the mechanisms leading to such modifications and their consequences for human health are complex, the authors advocate for investigation in larger population groups and also alert that such changes may be subject to interindividual variability and health status.
Abstract
Cholesterol-derived bile acids (BAs) affect numerous physiological functions such as glucose homeostasis, lipid metabolism and absorption, intestinal inflammation and immunity, as well as intestinal microbiota diversity. Diet influences the composition of the BA pool. In the present study, we analyzed the impact of a dietary supplementation with a freeze-dried blueberry powder (BBP) on the fecal BA pool composition. The diet of 11 men and 13 women at risk of metabolic syndrome was supplemented with 50 g/day of BBP for 8 weeks, and feces were harvested before (pre) and after (post) BBP consumption. BAs were profiled using liquid chromatography coupled with tandem mass spectrometry. No significant changes in total BAs were detected when comparing pre- vs. post-BBP consumption samples. However, post-BBP consumption samples exhibited significant accumulations of glycine-conjugated BAs (p = 0.04), glycochenodeoxycholic (p = 0.01), and glycoursodeoxycholic (p = 0.01) acids, as well as a significant reduction (p = 0.03) in the secondary BA levels compared with pre-BBP feces. In conclusion, the fecal bileacidome is significantly altered after the consumption of BBP for 8 weeks. While additional studies are needed to fully understand the underlying mechanisms and physiological implications of these changes, our data suggest that the consumption of blueberries can modulate toxic BA elimination.
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Prebiotic Potential of Herbal Medicines Used in Digestive Health and Disease.
Peterson, CT, Sharma, V, Uchitel, S, Denniston, K, Chopra, D, Mills, PJ, Peterson, SN
Journal of alternative and complementary medicine (New York, N.Y.). 2018;24(7):656-665
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Triphala, licorice and slippery elm are key treatments for gastrointestinal health and disease in traditional systems of medicine. Prebiotics are defined as undigested dietary carbohydrates that alter the gut microbiota and promote human health. They reach the site of action in the colon mostly unmetabolized and are broken down by enzymes. The aim of the study was to find out whether the complex carbohydrates present in herbal medicine may be strong drivers to modulate gut microbiota composition. The study recruited 12 healthy men and women, aged between 30-60 years who had previously followed a vegan or vegetarian diet for more than 1 year, to donate a single stool sample. Results show that both the sugar and protein content of these herbal medicines drive alterations in gut microbiota profiles. Each of these herbal medicines studied, uniquely altered gut bacteria communities. Authors conclude that the health benefits of these herbs are mostly due to their ability to alter the gut microbiota in a manner that is predicted to improve colonic epithelium function, reduce inflammation, and promote protection from bacterial pathogenic infection.
Abstract
INTRODUCTION The prebiotic potential of herbal medicines has been scarcely studied. METHODS The authors therefore used anaerobic human fecal cultivation to investigate whether three herbal medicines commonly used in gastrointestinal health and disease in Ayurveda alter the growth and abundance of specific bacterial species. RESULTS Profiling of cultures supplemented with Glycyrrhiza glabra, Ulmus rubra, or triphala formulation by 16S rDNA sequencing revealed profound changes in diverse taxa in human gut microbiota. Principal coordinate analysis highlights that each herbal medicine drives the formation of unique microbial communities. The relative abundance of approximately one-third of the 299 species profiled was altered by all 3 medicines, whereas additional species displayed herb-specific alterations. Herb supplementation increased the abundance of many bacteria known to promote human health, including Bifidobacterium spp., Lactobacillus spp., and Bacteroides spp. Herb supplementation resulted in the reduced relative abundance of many species, including potential pathogens such as Citrobacter freundii and Klebsiella pneumoniae. Herbal medicines induced blooms of butyrate- and propionate-producing species. U. rubra and triphala significantly increased the relative abundance of butyrate-producing bacteria, whereas G. glabra induced the largest increase in propionate-producing species. To achieve greater insight into the mechanisms through which herbal medicines alter microbial communities, the authors assessed the shifts in abundance of glycosyl hydrolase families induced by each herbal medicine. Herb supplementation, particularly G. glabra, significantly increased the representation and potential expression of several glycosyl hydrolase families. DISCUSSION These studies are novel in highlighting the significant prebiotic potential of medicinal herbs and suggest that the health benefits of these herbs are due, at least in part, to their ability to modulate the gut microbiota in a manner predicted to improve colonic epithelium function, reduce inflammation, and protect from opportunistic infection. Forthcoming studies in human clinical trials will test the concordance of the results generated in vitro and the predictions made by genome analyses.